Sludge is an inevitable by-product of the wastewater treatment process. Due to its high water content, large volume, and a large amount of toxic and hazardous substances, therefore it needs to be minimization and harmless treatment. However, sludge possesses extracellular polymeric substances (EPS) formed by ionization of negatively charged functional groups, which maintain a stable hydrated colloidal structure and prevent the release of water. This is a key factor in the difficulty of sludge dewatering. In the last decade, sulfate radical-based advanced oxidation processes (SR-AOPs) have received considerable attention due to their high efficiency for EPS disintegration, rapid reaction time and environmental friendliness, and thus sulfate radicals have become a new powerful tool for enhancing sludge dewaterability. In this paper, the development timeline and activation mechanisms of sulfate radicals were reviewed in detail, and the research advances of SR-AOPs for improving sludge dewaterability and removing micropollutants and heavy metals from sludge were systematically evaluated. Based on the current scientific problems of SR-AOPs in sludge conditioning, the future research directions of SR-AOPs were proposed from the perspectives of mechanism research, cost-effectiveness, and experimental scale, in order to provide a solid theoretical reference for sludge conditioning in wastewater treatment plants in China.